docs: def dynamic_sum(values, limit_n=1000, acc=0, depth=4):
      """Example of dynamic sum."""
      if len(values) < limit_n:
          return acc + sum(values)
  
      if depth > 0:
          half = len(values) // 2
          return add(
              dynamic_sum(values[:half], limit_n, acc, depth=depth-1),
              dynamic_sum(values[half:], limit_n, 0, depth=depth-1))
  
      return dynamic_sum(values[limit_n:], limit_n,
                         acc + sum(values[:limit_n]), depth)